Leyland Cypress is a fast growing columnar evergreen tree most often used for screening. Once established, it can grow three to four feet in a year. Its ultimate height is 60 – 70 feet with a spread of 8 to 10 feet. It is critical to be aware of the tree’s requirements so that it will grow to maturity. Leylands require full sun and adequate drainage, and should be planted 8 to 10 feet apart for good air circulation. The majority of nutrient absorbing roots exist in the upper 12 to 16 inches of the soil. Large trees require a minimum of 200 to 400 square feet of rooting area.
The tree has a thin bark which splits easily when temperatures are high and the soil is dry. Cold injury caused in winter when temperatures are less than thirty degrees at night followed by a daytime temperature in the sixties also cause the bark to split. Leylands are susceptible to several fungal problems which invade the tree at these cracks, wounds and natural openings.
| SEIRIDIUM | BOT CANKER | |
|---|---|---|
| Fungus | Seididium unicorne | Botryosphaeria dothidea |
| Vector | Wind, Water from rain & irrigation distribute spores. | Wind, Water from rain & irrigation distribute spores. |
| Entrance to tree | Wound, cracks, lenticles (natural openings) | Wound, cracks, lenticles (natural openings) |
| Prime Season | Early Spring | Spring and Summer |
| Symptoms – Initial | Small black dots barely visible to naked eye, | Spore causes canker which discolors cambium tissue. |
| Symptoms – Primary | Sap oozing from entry point. Sunken reddish, dark brown purplish cankers form on stems, branches, branch axils. Cambium layer red/brown color. | Bright, rust colored branches and yellowing or browning of shoots and branches. Diseased needles do not fall off. Little or no sap ooze. |
| Symptoms – Within one year | Dieback of foliage above canker. Needles will fall off. | Sunken, girdling canker at base of dead shoot or branch. | Symptoms – Year(s) Later | Much of tree dead. | Large cankers on trunk. Tree dying. |
| Controls – Chemical | None once infection takes place. | None once infection takes place. |
| Controls – Pruning | Prune 6 inches below canker. Disinfect tools after each cut. | Prune 6 inches below canker. Disinfect tools after each cut. |
| Prevention | Keep properly irrigated during periods of drought. | Keep properly irrigated during periods of drought. |
| Prevention | Avoid injury during planting or working around Leylands. | Avoid injury during planting or working around Leylands. |
| Prevention | Ensure sufficient air circulation and sunlight. | Ensure sufficient air circulation and sunlight. |
| Prevention | Destroy infected and pruned materials. | Destroy infected and pruned materials. |
| Prevention | Mulch several feet beyond lowest limbs. | Mulch several feet beyond lowest limbs. |